In 30 months, we collected 21 cases of primary cancers of the vulva at CHU-YO. These cancers are actually rare. They represented 5.3 % of all the gynaecological cancers diagnosed in the same period (396 cases). In Africa, all the authors agree that this cancer is rare but its proportion in relation to gynaecological cancers is highly variable, oscillating between 1.3 and 5 % [14, 17, 18]. In our study, cancer of the vulva was the 4th most common diagnosed gynaecological cancer in order of importance after cancer of the cervix, the uterus, and the ovary. In the literature, it is either the 4th or 5th gynaecological cancer [11, 19, 20]. The cancer of the uterus ranks first in the west European countries [21]. In Africa, it is that of the cervix [11, 20, 21]. The results from our study are based clinical observations, and might not be directly comparable with the ranking of incident cancers from cancer registries. The type and frequency of the factors favoring this situation vary from one country to another.
The cancer of the vulva is, classically speaking, a disease of elderly and menopausal women [1]. The average age of our patients was 55. In Africa, the average age varies between 46 and 61 [19, 22, 23]. Some average ages of 46 and 49 were noticed in Ghana and in Mali [19, 22]. But, in the western European, the average ages are over 70 [5] and in Overall, 55.7 % of the women were diagnosed at the age of 70 years and above [6]. The difference of the average ages between Europe and the less developed countries could be explained, by the difference of life expectancy at birth, which is 59 years in Burkina Faso against 85 years in France [24, 25] but also by the frequency of HPV infection in Africa [15, 16].
Two aetiological forms of vulvar cancer are classically described:
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The cancer of menopausal and elderly women resulting from chronic genital inflammatory diseases, associated with a mutation of gene P53. This cancer is frequent in developed countries where life expectancy is high [5, 6];
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The cancer developed from intra epithelial neoplasia due to the human papillomavirus infection [9, 10]. Each of our patients had already at least an episode of genital infection.
HIV infection was noticed in 6 out of 21 patients. The youngest of whom was 32. This rate is very high compared to the average prevalence rate of HIV infection in the adult population of Burkina Faso which is 1 % [26].
The HIV infection, through the resulting immunodepression is suspected to predispose to the cancer of the vulva [10]. The correlation between neoplasia of the low genital tractus and HIV is so important that the Center for Disease Control and Prevention has included high-grade dysplasias and in situ carcinomas as well, in the classification of HIV, with the invasive cancer of the cervix considered as a condition defining AIDS. Intra epithelial neoplasia of the vulva is also more frequent in HIV-infected women with a relative risk of 29 compared to the group of HIV-uninfected women [27]. Although human papillomavirus is strongly suspected to play an etiologic role in younger women [9, 28, 29], prevalence could not be confirmed in our series, because of the high cost of the diagnostic test. However, a previous study in our country noticed a strong relation between HPV infection and invasive cancers of the cervix [15].
HPV is one of the main risk factor of carcinomas of the low genital tractus. This led to some hope in the vaccines directed against the most frequent genotypes in Europe (16 and 18) [30]. The newly developed 9-valent vaccine [31] might be promising in the actual working context, because HPV genotypes seem to vary from one country to another, with the predominance of genotypes 52 (29.4 %) and 58 (20.6 %) in Ouagadougou [15]. A part from the infectious factors, many other risk factors were reported in the literature. Diabetes, obesity, hypertension, and atherosclerosis, sclerotic lichen, lupus, pemphigus vugaris are suspected to be the factors which are most frequently associated with vulvar cancers [11, 23]. In addition to these factors, in the researcher’s series, other factors that could be involved in the appearance of vulvar cancers were noticed. Nineteen (19/21) of the patients were having a scar due to female circumcision. The prevalence of female circumcision in the general population of those over 50 is not known in Burkina Faso. However, it is of 76 % among the age group 15–49 years and of 13.3 % in those below 15 [32]. Traditionally, the scars due to burns are risk factors of cutaneous carcinoma (Marjolin’s tumour) [33]. Yet, it has still not been reported in the literature that female circumcision can develop vulvar cancers. But the traditional use of heat repeatedly in order to heal wounds due to female circumcision could occasion real burns. Thus, the scars resulting from female circumcision could actually be like real scars due to burns, risk factors of carcinoma. However, from our observational study we cannot distinguish whether these are independent risk factors or merely coexisting medical conditions common to women of this age.
Similarly, the researcher could not come across, in the literature, cases of cancers of the vulva grown on lesions of vitiligo. However, this coexistence in almost half of the patients (9 cases/21), makes the researcher wonder whether vitiligo is not a risk factor of vulva cancer or whether both pathologies were not supported by the same subjacent physiological condition. Besides, though the relation with vitiligo is not well defined in the literature, some authors noticed this association. As it is reported in Carii et al., among the patients who presented an association of sclerotic lichen and vulvar cancer, 16 % had an antecedent of vitiligo [34].
From a clinical point of view, a mass, a plaque, an ulcer, a nodule, a genital pruritus, bleedings and post-menopausal vaginal losses, dyspareunia and inguinal adenopathies can be occasions for discovery [12]. Pain, ulceration, and tumefaction were the main reasons for consultation by our patients.
In the literature, the main localization remains the major labia. In 10 % of the cases, the lesions are extremely extensive and the primary site is difficult to define [9] as it is in 5/21 cases of our patients.
Just as it is in our series, the clinical aspect is chiefly an ulcero-granulating tumour in the literature [35]. All the authors agree on the most frequent histological type which is asquamous cell carcinoma [2, 34]. This is the case in our study in which there were 20 squamous cell carcinomas against only one basocellular carcinoma.
The evolution of vulvar cancers has long been locoregional, the ganglionary metastasias are premature and the distant metastasias are late [36]. In our study, only two patients (2/21) were at stage I or II contrasting with a small proportion of metastatic cases (3/21). These results are similar to the data in the African literature in which the time to first medical consultation was superior to 6 months in 60 % of the cases and 80 % of the patients were at stages III and IV of FIGO [14, 19, 37]. This contrasts with stage at diagnosis in the developed countries. In the USA, 90 % of cases are diagnosed in situ or at a premature stage of the invasive disease [38]. The diagnoses which are late, in the African environment might be due to the lack of awareness-raising [11] and mostly the sociocultural context. Indeed, in our context, the vulva is considered an area of decency and the patients only come for consultation when there appears an unbearable sign. This is the case of two of our patients who came on consultation when they saw a putrid perineal discharge and when they could not sit down. Unfortunately, when these signs appear, the tumor is already at an advanced stage. Let us also note the responsibility of some health workers who might diagnose the disease on time, just doing local care. Although there is no systematic screening for the cancer of the vulva, patients with history of cervical disease, might benefit from regular watch over. Likewise, patients with sclerotic lichens or with history of intraepithelial neoplasia should be educated to examine themselves through a mirror [2].
